From: Jean-Marc Valin
Date: Sun, 30 Oct 2011 20:58:56 +0000 (-0400)
Subject: draft: s/LSb/LSB/
X-Git-Tag: v0.9.7~14
X-Git-Url: http://git.xiph.org/?p=opus.git;a=commitdiff_plain;h=b77c44b46f46810ae9af3a1b88d361f1daeb769b
draft: s/LSb/LSB/
---
diff --git a/doc/draft-ietf-codec-opus.xml b/doc/draft-ietf-codec-opus.xml
index ba25d69c..0f4cfbb6 100644
--- a/doc/draft-ietf-codec-opus.xml
+++ b/doc/draft-ietf-codec-opus.xml
@@ -985,13 +985,13 @@ Raw bits are only used in the CELT layer.
0 1 2 3
7 6 5 4 3 2 1 0 7 6 5 4 3 2 1 0 7 6 5 4 3 2 1 0 7 6 5 4 3 2 1 0
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-| Range coder data (packed MSb to LSb) -> :
+| Range coder data (packed MSB to LSB) -> :
+ +
: :
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: |
@@ -1443,7 +1443,7 @@ An overview of the decoder is given in .
1: Range encoded bitstream
2: Coded parameters
-3: Pulses, LSb's, and signs
+3: Pulses, LSBs, and signs
4: Pitch lags, LTP coefficients
5: LPC coefficients and gains
6: Decoded signal (mono or mid-side stereo)
@@ -1655,7 +1655,7 @@ Each set contains one flag per 20 ms SILK frame.
, and 60 ms Opus frames use the
3-frame LBRR flag PDF.
For each channel, the resulting 2- or 3-bit integer contains the corresponding
- LBRR flag for each frame, packed in order from the LSb to the MSb.
+ LBRR flag for each frame, packed in order from the LSB to the MSB.
@@ -1829,7 +1829,7 @@ The quantized excitation signal (see ) follows
Non-zero pulse count
-Excitation LSb's
+Excitation LSBs
@@ -2086,7 +2086,7 @@ In an independently coded subframe gain, the 3 most significant bits of the
+ title="PDFs for Independent Quantization Gain MSB Coding">
Signal TypePDFInactive{32, 112, 68, 29, 12, 1, 1, 1}/256
@@ -2098,7 +2098,7 @@ In an independently coded subframe gain, the 3 most significant bits of the
The 3 least significant bits are decoded using a uniform PDF:
+ title="PDF for Independent Quantization Gain LSB Coding">
PDF{32, 32, 32, 32, 32, 32, 32, 32}/256
@@ -3982,7 +3982,7 @@ Unlike regular PVQ, SILK uses a variable-length, rather than fixed-length,
This encoding is better suited to the more Gaussian-like distribution of the
coefficient magnitudes and the non-uniform distribution of their signs (caused
by the quantization offset described below).
-SILK also handles large codebooks by coding the least significant bits (LSb's)
+SILK also handles large codebooks by coding the least significant bits (LSBs)
of each coefficient directly.
This adds a small coding efficiency loss, but greatly reduces the computation
time and ROM size required for decoding, as implemented in
@@ -4056,17 +4056,17 @@ Each block may have anywhere from 0 to 16 pulses, inclusive, coded using the
18-entry PDF in corresponding to the
rate level from .
The special value 17 indicates that this block has one or more additional
- LSb's to decode for each coefficient.
+ LSBs to decode for each coefficient.
If the decoder encounters this value, it decodes another value for the actual
pulse count of the block, but uses the PDF corresponding to the special rate
level 9 instead of the normal rate level.
This process repeats until the decoder reads a value less than 17, and it then
- sets the number of extra LSb's used to the number of 17's decoded for that
+ sets the number of extra LSBs used to the number of 17's decoded for that
block.
If it reads the value 17 ten times, then the next iteration uses the special
rate level 10 instead of 9.
The probability of decoding a 17 when using the PDF for rate level 10 is
- zero, ensuring that the number of LSb's for a block will not exceed 10.
+ zero, ensuring that the number of LSBs for a block will not exceed 10.
The cumulative distribution for rate level 10 is just a shifted version of
that for 9 and thus does not require any additional storage.
@@ -4220,34 +4220,34 @@ These partitions have nothing to code, so they require no PDF.
-
+
-After the decoder reads the pulse locations for all blocks, it reads the LSb's
+After the decoder reads the pulse locations for all blocks, it reads the LSBs
(if any) for each block in turn.
-Inside each block, it reads all the LSb's for each coefficient in turn, even
+Inside each block, it reads all the LSBs for each coefficient in turn, even
those where no pulses were allocated, before proceeding to the next one.
They are coded from most significant to least significant, and they all use the
PDF in .
-
+PDF{136, 120}/256
-The number of LSb's read for each coefficient in a block is determined in
+The number of LSBs read for each coefficient in a block is determined in
.
The magnitude of the coefficient is initially equal to the number of pulses
placed at that location in .
-As each LSb is decoded, the magnitude is doubled, and then the value of the LSb
+As each LSB is decoded, the magnitude is doubled, and then the value of the LSB
added to it, to obtain an updated magnitude.
-After decoding the pulse locations and the LSb's, the decoder knows the
+After decoding the pulse locations and the LSBs, the decoder knows the
magnitude of each coefficient in the excitation.
It then decodes a sign for all coefficients with a non-zero magnitude, using
one of the PDFs from .
@@ -4259,11 +4259,11 @@ Otherwise, it remains positive.
The decoder chooses the PDF for the sign based on the signal type and
quantization offset type (from ) and the
number of pulses in the block (from ).
-The number of pulses in the block does not take into account any LSb's.
+The number of pulses in the block does not take into account any LSBs.
Most PDFs are skewed towards negative signs because of the quantizaton offset,
but the PDFs for zero pulses are highly skewed towards positive signs.
If a block contains many positive coefficients, it is sometimes beneficial to
- code it solely using LSb's (i.e., with zero pulses), since the encoder may be
+ code it solely using LSBs (i.e., with zero pulses), since the encoder may be
able to save enough bits on the signs to justify the less efficient
coefficient magnitude encoding.
@@ -4348,7 +4348,7 @@ The constant quantization offset varies depending on the signal type and
Let e_raw[i] be the raw excitation value at position i, with a magnitude
composed of the pulses at that location (see
- ) combined with any additional LSb's (see
+ ) combined with any additional LSBs (see
), and with the corresponding sign decoded in
.
Additionally, let seed be the current pseudorandom seed, which is initialized